2-substituted-thio-2-cyclohexene-1-one and method for preparing them

ABSTRACT

2-Aliphatic- and arylthio-2-cyclohexen-1-ones are prepared by reacting a mercaptan (aliphatic or aryl) with 2,3epoxycyclohexanone in the presence of an alkaline catalyst. Using techniques such as described in U.S. Pat. No. 3,317,552, the product cyclic ketones can be dehydrogenated to 2-(aliphatic- and aryl-thio) phenols, which are converted to N-methylcarbamates by reaction with methyl isocyanate. These carbamates have insecticidal activity against the housefly and misquito larva (e.g., Metcalf et al., J. Agr. Food Chem., 13, 473 (1965)).

United States Patent 1 Tobias et al.

[ 1 Mar. 27, 1973 2-SUBSTITUTED-THIO-2- CYCLOI-IEXENE-l-ONE AND METHODFOR PREPARING THEM [75] Inventors: Michael A. Tobias, Edison; Jerry G.Strong, Westfield, both of NJ.

[73] Assignee: Mobil Oil Corporation, New York,

[22] Filed: July 11, 1968 [21] Appl. No.: 743,970

[52] U.S. Cl. ..260/586 R, 260/481 R, 260/609 F [51] Int. Cl. ..C07c49/30, C070 45/100 [58] Field of Search ..260/586 R [56] ReferencesCited UNITED STATES PATENTS 2,465,882 3/1949 Kendall et a1. 1.26O/586OTHER PUBLICATIONS Koe et al., Jour. Med. Chem. Vol. 7, pp. 705-709[1964].

Elderfield, Heterocyclic Compounds Vol. 1, pp. 29-30 [1950].

Moller, Chemistry of Org. Comp. 3rd Edition, pp. 148-149 [1965].

Primary Examiner-Bernard I-Ielfin Assistant ExaminerNorman MorgensternAtt0meyOswald G. Hayes, Donald L. Dickerson and Hastings S Trigg [57]ABSTRACT 6 Claims, No Drawings 2-SUBSTITUTED-THIO-2-CYCLOIIEXENE-l-ONEAND METHOD FOR PREPARING THEM BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention is concerned with novel 2-substitutedthio-2-cyclohexen-1-ones and a method for preparing them.

2. Description of the Prior Art Insofar as is now known, the2-substituted thio-2- cyclohexen-l-ones described herein and theirpreparation have not been disclosed in the prior art.

SUMMARY OF THE INVENTION This invention provides a process for producingcompounds having the formula:

wherein R is selected from the group consisting of alkyl (C -Chydroxyalkyl, (C -C alkaryl, phenyl, and halophenyl that comprisesreacting 2,3-epoxycyclohexanone with a mercaptan having the formula,RSH, wherein R is as defined above, in the presence of an alkalinecatalyst. It also provides these compounds as new compositions ofmatter. Using techniques such as described in U.S. Pat. No. 3,317,552,the product cyclic ketones can be dehydrogenated to 2-(aliphaticandaryl-thio) phenols, which are converted to N- methylcarbamates byreaction with methyl isocyanate. These carbamates have insecticidalactivity against the housefly and mosquito larva [e.g., Metcalf et al.;.I. Agr. Food Chem., 13, 473 (1965)].

DESCRIPTION OF SPECIFIC EMBODIMENTS The 2,3-epoxycyclohexanone used inpreparing the compounds of this invention is known in the art. It isreadily prepared by reacting 2-cyclohexen-l-one with hydrogen peroxide.

The mercaptan reactants are those having the formula, RSH, whereinv R isas defined hereinbefore. These compounds are well known and many areavailable commerically. Non-limiting examples of the mercaptans aremethyl mercaptan, isopropyl mercaptan, propyl mercaptan, isobutylmercaptan, sec-butyl mercaptan, amyl mercaptan, hexyl mercaptan,2-heptyl mercaptan, Z-ethylhexyl mercaptan, n-decyl mercaptan,3-hydroxypropyl mercaptan, 5-hydroxyamyl mercaptan, benzyl mercaptan,thiophenol (phenyl mercaptan), p-chlorothiophenol, m-bromothiophenol,and piodothiophenol.

The reaction between the 2,3-epoxycyclohexanone and the mercaptan iscarried out at temperatures between about C. and about 50 C. for aperiod -of time between about 0.5 hour and about 12 hours, using analkaline catalyst. Suitable catalysts include aqueous solutions ofsodium, potassium, or lithium hydroxide; alkali-metal alcoholates suchas sodium. methoxide and lithium ethoxide; ad organic bases such asbenzyltrimethylammonium hydroxide or methoxide.

Although the reaction can be carried out without use of a solvent, it ismore feasible to use one. Suitable sol- EXAMPLE 1 Three and eight-tenthsgrams (0.05 mole) of isopropyl mercaptan was dissolved in 10 ml. ofethanol and added dropwise over a 30 minute period to a solution of 5.6g. (0.05 mole) of 2,3-epoxycylohexanone, 6 drops of 15 per cent aqueoussodium hydroxide, and 25 m1. of ethanol. The reaction temperature wasmaintained at 35-40 C. throughout the addition. The reaction was stirredover night at room temperature, acidified with dilute hydrochloric acidand the solvent was removed at reduced pressure. Distillation of theresidue yielded 5.0 g. of 2-isopropylthio 2-cyc1ohexenl-one, b.p.109-1l2 (3 mm.).

EXAMPLE 2 Four and five-tenths grams-(0.05 mole) of isobutyl mercaptanwas dissolved in a 10 ml. of ethanol and added dropwise to a solutioncomposed of 5.6 g. (0.05 mole) of 2,3-epoxycyclohexanone, 6 drops of 15per cent aqueous sodium hydroxide and 25 ml. of ethanol. The reactionwas carried out and worked-up in exactly the same manner as wasdescribed in Example 1. Distillation of the product yielded 6.3 g. of2-isobutylthio-2- cyclohexen-l-one, b.p. 126-128 (3 mm.).

EXAMPLE 3 Six and two-tenths grams (0.05 mole) of benzyl mercaptan wasplaced in 5 ml. of methanol and added dropwise to asolution composed of5.6 g. of 2,3-epoxycyclohexanone, 6 drops of 15 per cent aqueous sodiumhydroxide, 30 ml. of water and 10 ml. of methanol. The reaction wascarried out and worked-up in exactly the same manner as was described inExample 1. Distillation of the product yielded 6.5 g. of Z-benzylthio-Z-cyclohexen-l-one, b.p. 155-158 (3 mm.).

EXAMPLE 4 Sixteen grams (0.11 mole) of p-chlorothiophenol in ml. ofmethanol containing 0.01 mole of sodium methoxide was added over 1 hourto a solution of 11.0

g. (0.1 mole) of 2,3-epoxycyclohexanone in 100 ml. of methanol. Afterstirring at 2535C. for 1 hour, the

methanol was removed and the residue was dissolved in methylenechloride. The organic solution was washed with per cent sodiumhydroxide, with water and with brine, dried over magnesium sulphate andconcentrated. Distillation yielded 14.1 g. of2-[(p-chlorophenyl)thio]-2-cyclohexen-1-one, b.p. l70-l73 (3 mm.).

Although the present invention has been described with preferredembodiments, it is to be understood that modifications and variationsmay be resorted to, without departing from the spirit and scope of thisinvention, as those skilled in the art will readily understand. Suchvariations and modifications are considered to be within the purview andscope of the appended claims.

What is claimed is;

1. Compounds having the formula:

wherein R is alkyl of one to ten carbon atoms.

2. 2-lsopropylthio-2-cyclohexen-1-one.

3. 2-lsobutylthio-2-cyclohexen-l-one.

4. A process for producing compounds defined in claim 1 that comprisesreacting 2,3-e'poxycyclohexanone with a mercaptan having the formula,RSH,, wherein R is alkyl (C -C in the presence of an alkaline catalyst.

5. A process for producing the compound of claim 2 that comprisesreacting 2,3-epoxycyclohexanone with isopropyl mercaptan in the presenceof an alkaline catalyst.

2. 2-Isopropylthio-2-cyclohexen-1-one.
 3. 2-Isobutylthio-2-cyclohexen-1-one.
 4. A process for producing compounds defined in claim 1 that comprises reacting 2,3-epoxycyclohexanone with a mercaptan having the formula, RSH, wherein R is alkyl (C1-C10) in the presence of an alkaline catalyst.
 5. A process for producing the compound of claim 2 that comprises reacting 2,3-epoxycyclohexanone with isopropyl mercaptan in the presence of an alkaline catalyst.
 6. A process for producing the compound of claim 3 that comprises reacting 2,3-epoxycyclohexanone with isobutyl mercaptan in the presence of an alkaline catalyst. 